Communication system and layout method of communication system

ABSTRACT

A communications system includes: a control device; a standard proxy input/output circuit configured to control a standard electric device; and an extension proxy input/output circuit configured to control an extension electric device. The control device and the standard proxy input/output circuit are provided on one substrate, and the control device and the extension proxy input/output circuit are connected to each other via an electric wire.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority ofJapanese Patent Application No. 2021-072003 filed on Apr. 21, 2021, theentire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a communication system and a layoutmethod of a communication system.

BACKGROUND

As a communication system, for example, an extension connector unit ofJP-A-2015-018694 is proposed. The extension connector unit ofJP-A-2015-018694 connects an extension input connector of an extensionmodule to an extension output connector of a base module, whenconnecting a load with the number of circuits that exceeds the number ofpins of the output connector of the base module to a control bus. As aresult, the load can be distributed and connected to the outputconnectors of the base module and the extension module.

SUMMARY

In the above-mentioned extension connector unit, the base module and theextension module are arranged on the same plane and connected to eachother by a connector. Therefore, there is a problem that a largearrangement space that can accommodate both the base module and theextension module arranged on the same plane is required.

The present disclosure is made in view of the above circumstances, andan object thereof is to provide a communication system that achievesreduction of space and a layout method of a communication system.

The present disclosure provides a communications system including: acontrol device; a standard proxy input/output circuit configured tocommunicate with the control device and control a standard electricdevice; and an extension proxy input/output circuit configured tocommunicate with the control device and control an extension electricdevice, wherein the control device includes: a first clock terminalconfigured to allow a clock to be output therefrom; a first inputterminal configured to allow an input signal to be input thereto; afirst output terminal configured to allow an output signal to be outputtherefrom; and a plurality of first selector terminals, each of theplurality of first selector terminals being configured to allow aselector signal to be output therefrom, the selector signal selecting acommunication destination, wherein each of the standard proxyinput/output circuit and the extension proxy input/output circuitincludes: a second clock terminal connected to the first clock terminal,the second clock terminal being configured to allow the clock to beinput thereto; a second output terminal connected to the first inputterminal, the second output terminal being configured to allow the inputsignal input to be output therefrom; a second input terminal connectedto the first output terminal, the second input terminal being configuredto allow the output signal to be input thereto; and a second selectorterminal connected to a corresponding one of the plurality of firstselector terminals, wherein the second selector terminal of the standardproxy input/output circuit and the second selector terminal of theextension proxy input/output circuit are connected to one of theplurality of first selector terminals and another of the plurality offirst selector terminals, respectively, wherein each of the standardproxy input/output circuit and the extension proxy input/output circuitis configured to communicate with the control device in synchronizationwith the clock in a case in which the selector signal is input to thesecond selector terminal, wherein the control device and the standardproxy input/output circuit are provided on one substrate, and whereinthe control device and the extension proxy input/output circuit areconnected to each other via an electric wire.

The present disclosure provides a layout method of a communicationsystem, the communication system including a control device, a standardproxy input/output circuit configured to communicate with the controldevice and control a standard electric device, and an extension proxyinput/output circuit configured to communicate with the control deviceand control an extension electric device, the layout method including:arranging the control device and the standard proxy input/output circuiton one substrate; arranging the one substrate and the extension proxyinput/output circuit in separated locations; and connecting the onesubstrate and the extension proxy input/output circuit with an electricwire.

The present disclosure can provide a communication system that achievesreduction of space and a layout method of a communication system.

The present disclosure is briefly described above. Details of thepresent disclosure will be further clarified by reading an aspect(hereinafter, referred to as an “embodiment”) for implementing theinvention to be described below with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit diagram showing a communication system according toa first embodiment; and

FIG. 2 is a circuit diagram showing a base substrate constituting acommunication system according to a second embodiment.

DETAILED DESCRIPTION

Specific embodiments according to the present disclosure will bedescribed below with reference to the accompanying drawings.

(First Embodiment)

First, a first embodiment will be described with reference to FIG. 1.FIG. 1 is a circuit diagram showing a communication system 1 accordingto the first embodiment. The communication system 1 of the presentembodiment is mounted on a vehicle. The communication system 1 includesa base substrate 2 and an extension substrate 3. The base substrate 2 isprovided with a microcomputer (hereinafter abbreviated as “μCOM”) 21 asa control device, a standard output large scale integration (LSI) 22 asa standard proxy input/output circuit, and a 5V power supply 23.

The μCOM 21 includes a memory (not shown) such as a read only memory(ROM) or a random access memory (RAM), and is constituted by a centralprocessing unit (CPU) that operates according to a program stored in thememory.

The μCOM 21 is connected to a CAN interface (I/F) 24 and is provided soas to be capable of CAN communication with a higher-level control device(not shown). The μCOM 21 is connected to an input I/F 25 and an outputI/F 26 so as to be capable of inputting to and output from an externaldevice. The CAN I/F 24, the input I/F 25, and the output IN 26 areprovided on the base substrate 2, and are all connected to a connectorC1, which is also provided on the base substrate 2. The connector C1 isconnected to a connector C2, which is attached to a terminal of a wireharness WH1. The wire harness WH1 connects the μCOM 21 to thehigher-level control device or the external device (not shown).

The μCOM 21 includes a first clock terminal CLK1 from which a clock isoutput, a first output terminal SO1 from which an output signal isoutput, a first input terminal SI1 to which an input signal is input,and two first chip selector terminals CS11 and CS12 as first selectorterminals from which Lo level selector signals that specify or selectcommunication destinations are output.

The standard output LSI 22 performs serial peripheral interface (SPI)communication with the μCOM 21. The standard output LSI 22 includes aplurality of output circuits (not shown) for supplying a drive signal toa standard electric device 10, and controls the output circuitsaccording to the communication with the μCOM 21 to control the standardelectric device 10. The standard electric device 10 is an electricdevice such as an LED or a relay coil that is commonly mounted on avehicle to be mounted. The standard output LSI 22 includes a secondclock terminal CLK21 connected to the first clock terminal CLK1 and towhich a clock is input, a second input terminal SI21 connected to thefirst output terminal SO1 and to which an output signal output from theμCOM 21 is input, a second output terminal S021 connected to the firstinput terminal SI1 and from which an input signal input to the μCOM 21is output, and a second chip selector terminal CS21 connected to thefirst chip selector terminal CS11.

The standard output LSI 22 is provided with a plurality of outputterminals PO1 connected to the plurality of output circuits (not shown)described above. The output terminals PO1 are connected to a connectorC3 provided on the base substrate 2. The connector C3 is connected to aconnector C4, which is attached to a terminal of a wire harness WH2. Thestandard output LSI 22 and the standard electric device 10 are connectedto each other by the wire harness WH2.

The first clock terminal CLK1, the first output terminal SO1, and thefirst chip selector terminal CS12 of the μCOM 21 are each connected to aplurality of electric wire terminals (not shown) constituting aconnector C5 via an output transistor (Tr) 27, respectively. The outputTr 27 and the connector C5 are provided on the base substrate 2. Thefirst input terminal SI1 of the μCOM 21 is connected to the electricwire terminals constituting the connector C5 via an I/F 28 constitutedby a resistor or the like. The I/F 28 is also provided on the basesubstrate 2. The connector C5 is connected to a connector C6, which isattached to a terminal of a wire harness WH3 as an electric wire. Thewire harness WH3 connects the μCOM 21 to an extension output LSI 31described later.

The 5V power supply 23 generates 5V from a power supply supplied via thewire harness WH1 and supplies the generated 5V to the μCOM 21 and thestandard output LSI 22.

The extension substrate 3 is equipped with the extension output LSI 31as an extension proxy input/output circuit and a 5V power supply 32. Theextension output LSI 31 includes a plurality of output circuits (notshown) for supplying a drive signal to an extension electric device 20,and controls the output circuits according to communication with theμCOM 21 to control the extension electric device 20. The extensionelectric device 20 is an electric device that is selectively mountedaccording to a specification of the vehicle to be mounted. The extensionelectric device 20 may be attached immediately before shipment of thevehicle, or may be retrofitted after shipment. When the extensionelectric device 20 is not mounted on the vehicle to be mounted, theextension substrate 3 is not connected to the base substrate 2 and isnot mounted on the vehicle to be mounted.

The extension output LSI 31 includes a second clock terminal CLK22connected to the first clock terminal CLK1 and to which a clock isinput, a second input terminal S122 connected to the first outputterminal SO1 and to which an output signal output from the μCOM 21 isinput, a second output terminal SO22 connected to the first inputterminal SI1 and from which an input signal to be input to the μCOM 21is output, and a second chip selector terminal CS22 connected to thefirst chip selector terminal CS12.

The extension output LSI 31 is provided with a plurality of outputterminals PO2 connected to the plurality of output circuits (not shown)described above. The output terminals PO2 are connected to a connectorC7 provided on the extension substrate 3. The connector C7 is connectedto a connector C8, which is attached to a terminal of a wire harnessWH4. The extension output LSI 31 and the extension electric device 20are connected to each other by the wire harness WH4.

The second clock terminal CLK22, the second input terminal SI22, and thesecond chip selector terminal CS22 of the extension output LSI 31 areeach connected to a connector C9 via an I/F 33, respectively. The I/F 33and the connector C9 are provided on the extension substrate 3. Thesecond output terminal SO22 of the extension output LSI 31 is connectedto the connector C9 via an output Tr 34. The output Tr 34 is alsoprovided on the extension substrate 3. The connector C9 is connected toa connector C10, which is attached to the other terminal of the wireharness WH3.

The wire harness WH3 includes a power supply line L1, a ground line L2,a clock line L3, an output line L4, an input line L5, and a selectorline L6. The power supply line L1 connects power supply lines betweenthe base substrate 2 and the extension substrate 3. The ground line L2connects ground lines between the base substrate 2 and the extensionsubstrate 3. The clock line L3 connects the first clock terminal CLK1 ofthe μCOM 21 to the second clock terminal CLK22 of the extension outputLSI 31, so that a clock flows. The output line

L4 connects the first output terminal SO1 of the μCOM 21 to the secondinput terminal SI22 of the extension output LSI 31, so that an outputsignal flows. The input line L5 connects the first input terminal SI1 ofthe μCOM 21 to the second output terminal SO22 of the extension outputLSI 31, so that an input signal flows. The selector line L6 connects thefirst chip selector terminal CS12 of the μCOM 21 to the second chipselector terminal CS22 of the extension output LSI 31, so that aselector signal flows.

The 5V power supply 32 generates 5V from a power supply supplied via thepower supply line L1 of the wire harness WH3 and supplies the generated5V to the extension output LSI 31.

Next, operations of the communication system 1 having theabove-described configuration will be described. First, the μCOM 21communicates with the higher-level control device by CAN communication,and communicates with the standard output LSI 22 and the extensionoutput LSI 31 according to a communication result. First, a case wherethe μCOM 21 communicates with the standard output LSI 22 will bedescribed. In this case, the μCOM 21 outputs a clock from the firstclock terminal CLK1 and outputs an Lo level selector signal from thefirst chip selector terminal CS11. Further, the μCOM 21 outputs a serialoutput signal from the first output terminal SO1 in synchronization withthe clock.

The output signal from the μCOM 21 is input to the second inputterminals SI21 and SI22 of both the standard output LSI 22 and theextension output LSI 31. When the Lo level selector signal is input fromthe second chip selector terminal CS21, the standard output LSI 22receives the output signal input to the second input terminal SI21 insynchronization with the clock for a corresponding bit. The standardoutput LSI 22 converts the received serial output signal into a parallelsignal and outputs the parallel signal from the output terminal PO1 tocontrol the standard electric device 10.

Since the selector signal from the second chip selector terminal CS22 isnot input to the extension output LSI 31, the output signal input to thesecond input terminal SI22 is ignored.

The standard output LSI 22 outputs, from the second output terminalSO21, an input signal indicating that the output signal insynchronization with the clock is received. The input signal output fromthe standard output LSI 22 is input to the first input terminal SI1 ofthe μCOM 21. While outputting the selector signal from the first chipselector terminal CS11, the μCOM 21 receives the input signal input tothe first input terminal SI1 as an input from the standard output LSI22.

Next, a case where the μCOM 21 communicates with the extension outputLSI 31 will be described. In this case, the μCOM 21 outputs a clock fromthe first clock terminal CLK1 and outputs a selector signal from thesecond chip selector terminal CS12. Further, the μCOM 21 outputs aserial output signal from the first output terminal SO1 insynchronization with the clock.

The output signal from the μCOM 21 is input to the second inputterminals S121 and S122 of both the standard output LSI 22 and theextension output LSI 31. When the Lo level selector signal is input, theextension output LSI 31 receives the output signal input to the secondinput terminal S122 in synchronization with the clock for acorresponding bit. The extension output LSI 31 converts the receivedserial output signal into a parallel signal and outputs the parallelsignal from the output terminal PO2 to control the extension electricdevice 20.

Since the selector signal from the second chip selector terminal CS21 isnot input to the standard output LSI 22, the output signal input to thesecond input terminal S121 is ignored.

The extension output LSI 31 outputs, from the second output signal SO22,an input signal indicating that an output signal in synchronization withthe clock is received. The input signal output from the extension outputLSI 31 is input to the first input terminal SI1 of the μCOM 21. Whileoutputting the selector signal from the first chip selector terminalCS12, the μCOM 21 receives the input signal input to the first inputterminal SI1 as an input from the extension output LSI 31.

Next, a layout method of the communication system 1 described above willbe described. The base substrate 2 and the extension substrate 3 arearranged at separated locations. For example, the base substrate 2 isarranged near the standard electric device 10, and the extensionsubstrate 3 is arranged near the extension electric device 20. The wireharness WH3 connects the base substrate 2 to the extension substrate 3.

According to the first embodiment described above, the μCOM 21 and thestandard output LSI 22 are provided on the same base substrate 2, andthe μCOM 21 and the extension output LSI 31 are connected to each othervia the wire harness WH3. Therefore, it is not necessary to arrange thebase substrate 2 and the extension substrate 3 on the same plane, andthe base substrate 2 and the extension substrate 3 can be arranged atseparated locations and connected by the wire harness WH3. Therefore,space can be reduced. Since the extension output LSI 31 is configured toreceive the clock and the output signal from the μCOM 21 and communicatewith the μCOM 21 only when the selector signal is input, the extensionoutput LSI 31 is configured in a simple way.

(Second Embodiment)

Next, a second embodiment will be described with reference to FIG. 2.FIG. 2 is a configuration diagram of a base substrate constituting thecommunication system 1 according to the second embodiment. In FIG. 2,the same reference numerals are given to the same portions as those inFIG. 1, which has already been described in the first embodiment, anddetailed description thereof will be omitted.

In the first embodiment described above, the base substrate 2 and theextension substrate 3 are connected to each other by the wire harnessWH3. Therefore, in particular, when a clock or an output signal flowsthrough the wire harness WH3, there is a problem that a risk ofradiation noise due to a square wave becoming noise of a radio or thelike increases. In the first embodiment, a clock and an output signalflow on the wire harness WH3 even while the μCOM 21 communicates withthe standard output LSI 22.

Therefore, in the second embodiment, an NOT circuit 291 and stopcircuits 292 and 293 are provided on the base substrate 2, and while theμCOM 21 communicates with the standard output LSI 22, the clock and theoutput signal are prevented from flowing in the wire harness WH3. TheNOT circuit 291 is connected to the first chip selector terminal C12 andinverts output of the first chip selector terminal C12. That is, the NOTcircuit 291 outputs a Hi level signal when an Lo level selector signalis output from the first chip selector terminal C12 in order for theμCOM 21 to communicate with the extension output LSI 31.

The stop circuit 292 is provided between the first clock terminal CLK1and the electric wire terminals (not shown) constituting the connectorC5 connected to the first clock terminal CLK1. The clock is input to oneof two inputs of the stop circuit 292, and an output of the NOT circuit291 is input to the other. The stop circuit 293 is provided between thefirst output terminal SO1 and the electric wire terminals (not shown)constituting the connector C5 connected to the first output terminalSO1. The output signal is input to one of two inputs of the stop circuit293, and the output of the NOT circuit 291 is input to the other.

The stop circuits 292 and 293 are constituted by, for example, ANDcircuits, and the Lo level selector signal is output from the first chipselector terminal C12, and the input clock or output signal is outputwhile the output of the NOT circuit 291 is at a Hi level. In the stopcircuits 292 and 293, the selector signal is not output from the firstchip selector terminal C12, and while the output of the NOT circuit 291is at an Lo level, the output of the input clock or output signal isstopped.

As a result, the stop circuits 292 and 293 can stop the output of theclock and the output signal to the extension output LSI 31 while theselector signal is not output from the first chip selector terminal C12.Arrangement positions of the stop circuits 292 and 293 will be describedin more detail. The base substrate 2 is provided with first wirings L21and L22 connected to the first clock terminal CLK1 and the first outputterminal SO1 of the μCOM 21, respectively, second wirings L31 and L32,which are branched from the first wirings L21 and L22 and connected tothe standard output LSI 22, and third wirings L41 and L42, which arebranched from the first wirings L21 and L22 and connected to theconnector C5. The stop circuits 292 and 293 are provided on the thirdwirings L41 and L42, respectively.

According to the second embodiment described above, since no clock oroutput signal flows through the wire harness WH3 when the selectorsignal is not output to the extension output LSI 31, it is possible toprevent generation of noise.

According to the second embodiment described above, when the selectorsignal is not output to the extension output LSI 31, the clock andoutput signal is stopped from being output to the extension output LSI31, and the clock and output signal is not stopped from being output tothe standard output LSI 22. By arranging the stop circuits 292 and 293on the third wirings L41 and L42, the stop circuits 292 and 293 do notstop outputting the clock and output signal to the standard output LSI22.

The present disclosure is not limited to the above embodiments, andmodifications, improvements, and the like can be made as appropriate. Inaddition, materials, shapes, dimensions, numbers, arrangement positions,and the like of components in the above embodiments are freely set andare not limited as long as the present disclosure can be achieved.

In the first and second embodiments described above, the output LSIs 22and 31 provided with the output circuits are used as the standard andextension proxy input/output circuits, but the present disclosure is notlimited thereto. An input LSI provided with an input circuit to whichstates (switch on, off, and the like) of the standard electric device 10and the extension electric device 20 may also be used as the standardand extension proxy input/output circuits.

Here, features of the above-mentioned embodiments of the communicationsystem and the layout method of a communication system according to thepresent disclosure are briefly summarized and listed below in [1] to[4], respectively.

[1] A communications system (1), including:

a control device (21);

a standard proxy input/output circuit (22) configured to communicatewith the control device (21) and control a standard electric device(10); and an extension proxy input/output circuit (31) configured tocommunicate with the control device (21) and control an extensionelectric device (20),

wherein the control device (21) includes:

-   -   a first clock terminal (CLK1) configured to allow a clock to be        output therefrom;    -   a first input terminal (SI1) configured to allow an input signal        to be input thereto;    -   a first output terminal (SO1) configured to allow an output        signal to be output therefrom; and

a plurality of first selector terminals (CS11, CS12), each of theplurality of first selector terminals (CS11, CS12) being configured toallow a selector signal to be output therefrom, the selector signalspecifying a communication destination,

wherein each of the standard proxy input/output circuit (22) and theextension proxy input/output circuit (31) includes:

-   -   a second clock terminal (CLK21, CLK22) connected to the first        clock terminal (CLK1), the second clock terminal (CLK21, CLK22)        being configured to allow the clock to be input thereto;    -   a second output terminal (SO21, SO22) connected to the first        input terminal (SI1), the second output terminal (SO21, SO22)        being configured to allow the input signal input to be output        therefrom;    -   a second input terminal (SI21, SI22) connected to the first        output terminal (SO1), the second input terminal (SI21, SI22)        being configured to allow the output signal to be input thereto;        and    -   a second selector terminal (CS21, CS22) connected to a        corresponding one of the plurality of first selector terminals        (CS11, CS12),

wherein the second selector terminal (CS21) of the standard proxyinput/output circuit (22) and the second selector terminal (CS22) of theextension proxy input/output circuit (31) are connected to one of theplurality of first selector terminals (CS11, CS12) and another of theplurality of first selector terminals (CS11, CS12), respectively,

wherein each of the standard proxy input/output circuit (22) and theextension proxy input/output circuit (31) is configured to communicatewith the control device (21) in synchronization with the clock in a casein which the selector signal is input to the second selector terminal(CS21, CS22),

wherein the control device (21) and the standard proxy input/outputcircuit (22) are provided on one substrate (2), and

wherein the control device (21) and the extension proxy input/outputcircuit (31) are connected to each other via an electric wire (WH3).

[2] The communication system (1) according to [1],

wherein the one substrate (2) is provided with an electric wire terminalfor connecting to the electric wire (WH3), and

wherein the communication system (1) further comprises a stop circuit(292, 293) configured to stop outputting the clock and the output signalfrom the electric wire terminal to the extension proxy input/outputcircuit (31) in a case in which the selector signal is not output fromthe first selector terminal (CS12) connected to the extension proxyinput/output circuit (31).

[3] The communication system (1) according to [2],

wherein the substrate (2) is provided with a first wiring (L21, L22)connected to each of the first clock terminal (CLK1) and the firstoutput terminal (SO1), a second wiring (L31, L32) branched from thefirst wiring (L21, L22) and connected to the standard proxy input/outputcircuit (22), and a third wiring (L41, L42) branched from the firstwiring (L21,

L22) and connected to the electric wire terminal, and

wherein the stop circuit (292, 293) is provided on the third wiring(L41, L42).

[4] A layout method of a communication system (1), the communicationsystem (1) including a control device (21), a standard proxyinput/output circuit (22) configured to communicate with the controldevice (21) and control a standard electric device (10), and anextension proxy input/output circuit (31) configured to communicate withthe control device (21) and control an extension electric device (20),the layout method including:

arranging the control device (21) and the standard proxy input/outputcircuit (22) on one substrate (2);

arranging the substrate (2) and the extension proxy input/output circuit(31) in separated locations; and

connecting the substrate (2) and the extension proxy input/outputcircuit (31) with an electric wire (WH3).

According to the communication system and the layout method of acommunication system having configurations in the above [1] and [4], itis not necessary to arrange the substrate on which the standard proxyinput/output circuit is mounted and a substrate on which the extensionproxy input/output circuit is mounted on the same plane, and they can bearranged in separated locations and connected by the electric wire.Therefore, space can be reduced. Since the extension proxy input/outputcircuit is configured to receive the clock and the output signal fromthe control device and communicate with the control device only in acase in which the selector signal is input, a simplified configurationcan be achieved.

According to the communication system having a configuration in theabove [2], since no clock or output signal flows through the electricwire in a case in which the selector signal is not output to theextension proxy input/output circuit, generation of noise can beprevented.

According to the communication system having a configuration in theabove [3], in the case in which the selector signal is not output to theextension proxy input/output circuit, the clock and the output signalcan be stopped from being outputting to the extension proxy input/outputcircuit, and the clock and the output signal are not stopped from beingoutputting to the standard proxy input/output circuit.

1. A communications system comprising: a control device; a standardproxy input/output circuit configured to communicate with the controldevice and control a standard electric device; and an extension proxyinput/output circuit configured to communicate with the control deviceand control an extension electric device, wherein the control devicecomprises: a first clock terminal configured to allow a clock to beoutput therefrom; a first input terminal configured to allow an inputsignal to be input thereto; a first output terminal configured to allowan output signal to be output therefrom; and a plurality of firstselector terminals, each of the plurality of first selector terminalsbeing configured to allow a selector signal to be output therefrom, theselector signal specifying a communication destination, wherein each ofthe standard proxy input/output circuit and the extension proxyinput/output circuit comprises: a second clock terminal connected to thefirst clock terminal, the second clock terminal being configured toallow the clock to be input thereto; a second output terminal connectedto the first input terminal, the second output terminal being configuredto allow the input signal input to be output therefrom; a second inputterminal connected to the first output terminal, the second inputterminal being configured to allow the output signal to be inputthereto; and a second selector terminal connected to a corresponding oneof the plurality of first selector terminals, wherein the secondselector terminal of the standard proxy input/output circuit and thesecond selector terminal of the extension proxy input/output circuit areconnected to one of the plurality of first selector terminals andanother of the plurality of first selector terminals, respectively,wherein each of the standard proxy input/output circuit and theextension proxy input/output circuit is configured to communicate withthe control device in synchronization with the clock in a case in whichthe selector signal is input to the second selector terminal, whereinthe control device and the standard proxy input/output circuit areprovided on one substrate, and wherein the control device and theextension proxy input/output circuit are connected to each other via anelectric wire.
 2. The communication system according to claim 1, whereinthe one substrate is provided with an electric wire terminal forconnecting to the electric wire, and wherein the communication systemfurther comprises a stop circuit configured to stop outputting the clockand the output signal from the electric wire terminal to the extensionproxy input/output circuit in a case in which the selector signal is notoutput from the first selector terminal connected to the extension proxyinput/output circuit.
 3. The communication system according to claim 2,wherein the substrate is provided with a first wiring connected to eachof the first clock terminal and the first output terminal, a secondwiring branched from the first wiring and connected to the standardproxy input/output circuit, and a third wiring branched from the firstwiring and connected to the electric wire terminal, and wherein the stopcircuit is provided on the third wiring.
 4. A layout method of acommunication system, the communication system comprising a controldevice, a standard proxy input/output circuit configured to communicatewith the control device and control a standard electric device, and anextension proxy input/output circuit configured to communicate with thecontrol device and control an extension electric device, the layoutmethod comprising: arranging the control device and the standard proxyinput/output circuit on one substrate; arranging the one substrate andthe extension proxy input/output circuit in separated locations; andconnecting the one substrate and the extension proxy input/outputcircuit with an electric wire.